Hi there - I am looking at methods of sensing current in an Avalanche
> PhotoDiode (APD). Typical current in them is along the lines of 100 nA
> to 1 mA. I'm trying to figure out how to sense current in the buggers.
> Here is what I think I need:
Look, I'm no expert, but what's wrong with a "virtual ground" transconductance opamp circuit? Don't current sources "like" working into shorts?
> So - is this at all possible? Can anybody point me down the right
> path? I'm not even sure what sort of technique I should be using with
> this - resistive shunt, transformer, hall effect, etc.
>
Neither do I, but these guys at least sell something like it
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I have a much older DC current probe, DC-50MHz, and it uses a complicated feedback circuit combining the output of a Hall sensor and a transformer. I don't understand how it works, but it does.
Anyways, what's wrong with a resistor? Too noisy?